Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of materials over a semiconductor substrate, and patterning the various material layers using lithography to form an integrated circuit (IC) and elements thereon. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed.
During the manufacturing of the semiconductor devices, various processing steps are used to fabricate integrated circuits on a semiconductor wafer. One of the difficult factors in the continuing evolution toward smaller device size and higher density has been the ability to consistently form small critical dimensions within predetermined error windows. For example, semiconductor feature sizes are frequently subjected to optical or electrical metrology inspections following photolithographic patterning and etching to ensure that critical dimensions are within acceptable limits.
Although existing methods and devices for operating the processing steps have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects. Consequently, it would be desirable to provide a solution for the process control for semiconductor manufacturing operations.